排序方式: 共有147条查询结果,搜索用时 15 毫秒
141.
A series of studies using farnesyltransferase (FTase) inhibitors that the inhibition of FTase function suppresses the growth of ras-transformed cells in vitro and in vivo. However, whether FTase is directly involved in the regulation of cell proliferation remains to be demonstrated. To investigate whether overexpression of FTase results in altered cell growth and transformation, we thus used NIH3T3 cells transfected with cDNA constructs of both alpha and beta subunits of human FTase. FTase-overexpressing cells resulted in a 3- to 13-fold increase in the expression of the alpha and beta subunit protein of FTase and a 1.5- to 3-fold increase in the level of the enzyme activity compared with untransfected NIH3T3 cells or vector-transfected cells. Further investigations using metabolic labeling indicated that farnesylation of Ras was enhanced in FTase-overexpressing cells. Insulin-like growth factor-I, platelet-derived growth factor (PDGF), and basic fibroblast growth factor (bFGF) more potently enhanced DNA synthesis and anchorage-dependent growth in FTase-overexpressing cells than in control cells, in a dose-dependent manner. In particular, PDGF and bFGF also induced dose-dependently enhanced colony formation in soft agar in FTase-overexpressing cells. Furthermore, in FTase-transfectants, bFGF stimulated high activation of mitogen-activated protein kinase. Interestingly, FTase-transfectants developed progressive tumors in nude mice. Light and electron microscopy showed that the tumors were characteristic of fibrosarcoma, which were distinct from v-ras-induced tumors. Overexpression of FTase in NIH3T3 cells thus amplifies growth-factor-mediated cell growth and transformation, and FTase-overexpressing cells form tumors in nude mice. 相似文献
142.
143.
We report our experience with five lesions exclusively involving the entire cavernous sinus in which an essentially extradural surgical approach was used. There were two cases of cavernous haemangioma, two cases of meningioma and one case of fungal granuloma. The dural cover of the superior orbital fissure, and mandibular and maxillary divisions of the fifth nerve was dissected along with the dura of the lateral wall of the cavernous sinus. The presence of a relatively large intracavernous bulge due to the tumour assisted in this dissection. The contents of the cavernous sinus were exposed from an anterolateral, lateral and inferior approach. Through the corridor available between the splayed out cranial nerves, a radical resection of the tumour was accomplished in each case. The technical advantages of this approach are discussed in light of the anatomy of the dural configuration of the lateral wall of the cavernous sinus. 相似文献
144.
145.
146.
RB del Rosario YW Jung KE Baidoo SZ Lever DM Wieland 《Canadian Metallurgical Quarterly》1994,21(2):197-203
Fifty-six asthmatics from an asthma ward or from an asthma out-patient clinic were challenged with two low concentrations (0.03 and 0.012 mg) of metacholine chloride in order to assess the relationship between pronounced hyper-responsiveness and asthma severity in a clinical setting. Only inhaled bronchodilators were stopped before challenge. Asthma severity was assessed retrospectively and prospectively on the basis of treatment, number of days in hospital, intensive care, number of emergency visits and days on sick-leave. The results show that pronounced hyper-responsiveness (n = 28) is not associated with asthma severity. It is concluded that a single simplified test of pronounced bronchial hyper-responsiveness, performed without taking into consideration the actual state of the disease and without stopping all medication, is of no help in identifying the patients with the clinically most severe asthma and worst prognosis. 相似文献
147.